1. Field of the Invention
The present invention relates to injection molding machines and, more particularly, to an injection molding machine equipped with a device for the mechanized exchange of injection molding dies and to a safety cover arrangement for the die exchange mechanism of such a machine.
2. Description of the Prior Art
It is known to employ mechanisms for the automatic removal and insertion of die sections in injection molding machine in conjunction with the production of plastic parts with metal inserts, for example. One such mechanism is disclosed in my U.S. Pat. No. 3,973,888. The presence of a mechanized die handling device requires the arrangement of a safety cover, or covers, for the protection of the machine operator.
In the case of the die exchange mechanism of U.S. Pat. No. 3,973,888, the safety cover is a large cross-sectionally L-shaped cover panel with a vertical panel wall covering the front side of a die transfer table and a horizontal panel wall covering the upper side of the transfer table. The safety cover is guided for longitudinal opening displacements to either side of the transfer table so that, alternatingly, a left-hand and a right-hand die position on the transfer table is exposed for access by the operator. Such a safety cover is illustrated in the advertising folder entitled "Erhohte Wirtschaftlichkeit mit Arburg Schiebetisch", and distributed by Arburg Maschinenfabrik Hehl & Sohne, 7298 Lossburg, Germany.
A major shortcoming of a one-piece safety cover of this type relates to the fact the the open cover extends laterally beyond the width of the injection molding machine, thereby presenting a potential hazard to an unsuspecting person in the vicinity of the machine, including the risk of being struck by the cover executing an opening movement. These machines also require more floor space, especially when arranged in a row of parallel oriented machines.
An additional shortcoming of this type of safety cover is that it does not lend itself to use with a die exchange mechanism which is designed for handling die assemblies with attached temperature preconditioning lines, as is the case with a device disclosed in my two copending U.S. patent applications Ser. No. 506,025 now U.S. Pat. No. 4,462,783 and Ser. No. 506,026, now U.S. Pat. No. 4,518,338 filed 20 June 1983. A cover for such a device must provide access for the attachment of the supply line harness at the die assembly on the translation table, as well as movement freedom for the attached harness during the longitudinal translation movement and the subsequent lateral transfer movement of the injection molding die.